Operating system file caching mechanism

What is a file system? a. The organization of data, or files, on the secondary storage devices b. The organization of data in main memory c. The disk controllers that allow the operating system to access disk drivces d. The operating system file caching mechanisms. Which Windows file system provides the most security? a. EXT3 b. FAT c. FAT32 d. NTFS Where are UNIX file system permissions stored? a. Registry b. File mode field c. Domain security database d. Domain ACE